The transition G-->A at position 506 of the factor V gene is responsible for resistance to the anticoagulant effect of activated protein C (APC-resistance), and represents the most common hereditary risk factor for venous thrombosis. A comparison of the ability of non-radioactive single-strand conformation polymorphism (SSCP) and of a standard PCR procedure followed by further digestion with MnlI to detect this factor V gene (FVQ 506) transition indicates that these is a good agreement between the two methods. Non-radioactive SSCP analysis therefore represents a rapid and sensitive alternative for the diagnosis of this important point mutation.41379-81